A compilation video of Sawyer slurring her words began circulating on social media and made news headlines in the US.

The clip most talked about showed Sawyer calling excitedly for music, saying: "Okay, I wanna - can we have our music, because this is another big one here. Minnesota, we're ready to project Minnesota, right now. Well, tonight we know that President Orama - Obama - has won Minnesota."

US entertainment news site Gawker went further: "She slurred every other word, rambled about the lack of music, and asked a correspondent if the exclamation point in the Obama slogan represented the direction he truly wanted to go with his presidency. What more proof do you need?"

Today a representative for Sawyer spoke out in her defence, denying she was not drunk or on drugs and was instead just "exhausted".

"Diane's been up for days and she's had many sleepless nights. She was covering the hurricane and then preparing for the election broadcast," the representative toldthe Daily Mail.

It is not the first time Sawyer's on-air appearance prompted speculation she had been drinking.

In 2009 she reportedly appeared tipsy covering the inauguration of Barack Obama - at the time her representatives also said she was not drunk and just exhausted.